From: Atsushi Nemoto <atsushi.nemoto@xxxxxxxxxx>
[ Upstream commit 5d4c7977499a736f3f80826bdc9744344ad55589 ]
Use a mutex to protect access to idev->msg_len, idev->buf, etc. which
are modified by both altr_i2c_xfer_msg() and altr_i2c_isr().
This is the minimal fix for easy backporting. A cleanup to remove the
spinlock will be added later.
Signed-off-by: Atsushi Nemoto <atsushi.nemoto@xxxxxxxxxx>
Acked-by: Thor Thayer <thor.thayer@xxxxxxxxxxxxxxx>
[wsa: updated commit message]
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-altera.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c
index 92d2c706c2a7..a60042431370 100644
--- a/drivers/i2c/busses/i2c-altera.c
+++ b/drivers/i2c/busses/i2c-altera.c
@@ -70,6 +70,7 @@
* @isr_mask: cached copy of local ISR enables.
* @isr_status: cached copy of local ISR status.
* @lock: spinlock for IRQ synchronization.
+ * @isr_mutex: mutex for IRQ thread.
*/
struct altr_i2c_dev {
void __iomem *base;
@@ -86,6 +87,7 @@ struct altr_i2c_dev {
u32 isr_mask;
u32 isr_status;
spinlock_t lock; /* IRQ synchronization */
+ struct mutex isr_mutex;
};
static void
@@ -245,10 +247,11 @@ static irqreturn_t altr_i2c_isr(int irq, void *_dev)
struct altr_i2c_dev *idev = _dev;
u32 status = idev->isr_status;
+ mutex_lock(&idev->isr_mutex);
if (!idev->msg) {
dev_warn(idev->dev, "unexpected interrupt\n");
altr_i2c_int_clear(idev, ALTR_I2C_ALL_IRQ);
- return IRQ_HANDLED;
+ goto out;
}
read = (idev->msg->flags & I2C_M_RD) != 0;
@@ -301,6 +304,8 @@ static irqreturn_t altr_i2c_isr(int irq, void *_dev)
complete(&idev->msg_complete);
dev_dbg(idev->dev, "Message Complete\n");
}
+out:
+ mutex_unlock(&idev->isr_mutex);
return IRQ_HANDLED;
}
@@ -312,6 +317,7 @@ static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg)
u32 value;
u8 addr = i2c_8bit_addr_from_msg(msg);
+ mutex_lock(&idev->isr_mutex);
idev->msg = msg;
idev->msg_len = msg->len;
idev->buf = msg->buf;
@@ -336,6 +342,7 @@ static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg)
altr_i2c_int_enable(idev, imask, true);
altr_i2c_fill_tx_fifo(idev);
}
+ mutex_unlock(&idev->isr_mutex);
time_left = wait_for_completion_timeout(&idev->msg_complete,
ALTR_I2C_XFER_TIMEOUT);
@@ -409,6 +416,7 @@ static int altr_i2c_probe(struct platform_device *pdev)
idev->dev = &pdev->dev;
init_completion(&idev->msg_complete);
spin_lock_init(&idev->lock);
+ mutex_init(&idev->isr_mutex);
ret = device_property_read_u32(idev->dev, "fifo-size",
&idev->fifo_size);
--
2.25.1
